# Extension and tests of atomic structure theory techniques

High-precision atomic physics experiments play an important role in testing the Standard Model of particle physics at low energy. Highly accurate atomic structure calculations are required in order to interpret the experiments in terms of fundamental physics parameters. Atomic physics calculations involve treating the many-electron atomic Hamiltonian approximately. In order to achieve high accuracy, a number of many-body effects need to be taken into account using perturbation theory. This project is to continue to develop and test techniques for extending many-body methods for high-precision calculations of atomic systems.

In particular, one such class of effects, known as "ladder diagrams", are missing from some calculations. Though small, these corrections seem to be important in some cases. The ladder-diagram method has been applied previously to energies with high success (see: Physical Review A, 78, 042502.) The plan here is to extend this method to include "ladder diagram" corrections directly into atomic wavefunctions. These wavefunctions can then be used to compute relevant atomic properties (for example, hyperfine splittings, transition rates, lifetimes etc.). The project will involve aspects of quantum mechanics (elementary atomic theory) and numerical methods (application of existing code libraries to new problems in atomic physics). It will also involve some basic programming (in c++ and/or fortran), though no prior knowledge of programming is required.